Myasthenia gravis with a paraneoplastic marker

Area of Science:

• Neurology
• Oncology
• Immunology

Background:

• Ocular manifestations are common in myasthenia gravis and Lambert-Eaton syndrome.
• Both conditions are frequently associated with lung carcinoma.
• Overlap between myasthenia gravis and Lambert-Eaton syndrome presents diagnostic challenges.

Observation:

• A case study of a patient with a history of lung carcinoma presenting with fatigable diplopia and ptosis.
• The patient exhibited positive test results for acetylcholine receptor antibodies (myasthenia gravis) and N-type voltage-gated calcium channel antibodies.
• Importantly, P/Q-type voltage-gated calcium channel antibodies, indicative of Lambert-Eaton syndrome, were negative.

Findings:

• Serological autoantibody profiles can distinguish paraneoplastic myasthenia gravis from Lambert-Eaton syndrome.
• The presence of acetylcholine receptor antibodies confirmed myasthenia gravis.
• The absence of P/Q-type VGCC antibodies ruled out typical Lambert-Eaton syndrome, despite the presence of N-type VGCC antibodies.

Implications:

• Accurate serological distinction is crucial for appropriate patient management.
• Understanding autoantibody profiles aids in diagnosing paraneoplastic syndromes.
• This case highlights the importance of comprehensive antibody testing in patients with neurological symptoms and a history of lung cancer.